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Rear upper control arms- Camber discussion

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#101
Steve Scheifler

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Yep, you are new :) but that’s OK.

The problems with a max camber rule can’t be solved with a special tool, but unless you understand how it all works on these cars, how it is measured and the reasons it can change, there is no way to explain why it’s a bad idea. In fact, if you understood all that along with how “max” values are treated in the real world, there would be no need to explain why such a rule is a bad idea.
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#102
Steve Scheifler

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Brandon,

Clearly we are deadlocked :). I see nothing but holes in your logic as you do mine, and we probably each have a lot of others on our side. We won’t change, but because there may still be some on the fence I’ll close with a few final thoughts, somewhat redundant perhaps but seemingly brushed aside last time.

That you do your own R&R of parts is great, many out there cannot for a variety of reasons. But this is largely about setup which you don’t do yourself or apparently understand fully. No point debating that, so sticking with just the cost your experience described above is not exactly typical.

East Street lists more NB rear crossmembers online than probably any 10 other salvage yards combined and they get $175. That’s just the subframe, no suspension. Most people can’t count on finding one locally when they suddenly need one quickly so add on shipping, say $75. How many are unable to do their own R&R? A bunch. So they need to find a competent shop willing to work on a race car (not all will) and drag the car over there. Labor isn’t cheap and then the entire rear alignment needs to be redone since both sides come apart. Even at a shop specializing in these cars that adds up, and if you are stuck with a general import shop the chances of attention to detail aren’t great. Dave, you guys can do the job blindfolded and fast, what would your shop charge to replace the rear subframe and realign it? I’m guessing it’s a lot less than most can have it done properly for in their area. And if that doesn’t solve their problem, then what??

Ah well, I’ve looked at this from different angles and other than just plain obstinance against the perception of “giving in” or “rules creep” I have not read a single cogent argument against providing a cheap and easy way for everyone to get as much camber as they like, while the reasons for it are numerous and obvious. It’s easy for you, or someone who runs a race shop, to say “get new parts” like there is nothing to it but the reality is quite different for most. If the delay in pulling all that together doesn’t make them miss a race then the hit to a tight budget might, and I’m damn sure the club would prefer to see that money spent on entry fees.

I’m done. If anyone is serious about wanting something like this they should start a letter writing drive to the SMAC and CRB, but I wouldn’t hold out much hope.
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#103
Ron Alan

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As much as I hate to say it, I agree with Brandon. 

 

Dave

Which comes first? The slap or the kiss? :)


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#104
Brandon

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Brandon,

Clearly we are deadlocked :). I see nothing but holes in your logic as you do mine, and we probably each have a lot of others on our side. We won’t change, but because there may still be some on the fence I’ll close with a few final thoughts, somewhat redundant perhaps but seemingly brushed aside last time.

That you do your own R&R of parts is great, many out there cannot for a variety of reasons. But this is largely about setup which you don’t do yourself or apparently understand fully. No point debating that, so sticking with just the cost your experience described above is not exactly typical.

East Street lists more NB rear crossmembers online than probably any 10 other salvage yards combined and they get $175. That’s just the subframe, no suspension. Most people can’t count on finding one locally when they suddenly need one quickly so add on shipping, say $75. How many are unable to do their own R&R? A bunch. So they need to find a competent shop willing to work on a race car (not all will) and drag the car over there. Labor isn’t cheap and then the entire rear alignment needs to be redone since both sides come apart. Even at a shop specializing in these cars that adds up, and if you are stuck with a general import shop the chances of attention to detail aren’t great. Dave, you guys can do the job blindfolded and fast, what would your shop charge to replace the rear subframe and realign it? I’m guessing it’s a lot less than most can have it done properly for in their area. And if that doesn’t solve their problem, then what??

Ah well, I’ve looked at this from different angles and other than just plain obstinance against the perception of “giving in” or “rules creep” I have not read a single cogent argument against providing a cheap and easy way for everyone to get as much camber as they like, while the reasons for it are numerous and obvious. It’s easy for you, or someone who runs a race shop, to say “get new parts” like there is nothing to it but the reality is quite different for most. If the delay in pulling all that together doesn’t make them miss a race then the hit to a tight budget might, and I’m damn sure the club would prefer to see that money spent on entry fees.

I’m done. If anyone is serious about wanting something like this they should start a letter writing drive to the SMAC and CRB, but I wouldn’t hold out much hope.

 

Steve,

I know enough about setup but don't have the facilities or tools to do it. That's certainly not "don't...apparently understand fully." That's the crux of this entire thread is the presumption (PRESUMPTION) these slotted arms were entirely and 100% in support of gaining more negative camber.

 

It is my position this is NOT the case and there is another reason why they were slotted that has not been identified.

If they were to be slotted towards the centerline of the vehicle at a downward angle, that would gain camber and enable a taller ride height, this removing the negatives of running lower (less suspension travel) while retaining the negative camber gained by running lower.

 

Sheesh! I'm happy to debate this outside of a monetary view yet no one seems willing to do so. Especially yourself by murdering more words about subframe availability and their relative costs. Your respective high horse of "looked at this from different angles" is fine and dandy but you're part of the problem when it comes to people who get caught cheating: "Make their mod legal!"

 

That's not how this work, that's not how any of this works.

 

And Ron, if he shaves it won't be a slap...


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#105
Steve Scheifler

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People may be ducking your question for various reasons including that it wasn’t very clear, leading to my doubts about your understanding. Why not simply spit out your exact concern or theory?

But since you persist, my thoughts. Obviously, getting more camber via the arm allows you to get more without going as low as you would otherwise need to. Running lower is better in some ways and worse in others, so the slotted arm allows more flexibility to find a happy combination. That’s not news, it’s the whole point of this topic.

An angled slot compared to a horizontal one simply changes the angle of the arm itself. That in turn impacts suspension geometry such as roll center which is likely subterranean for us. Ideally we’d like to raise the inner pivot points of ALL arms so that when the car is lowered the arms are all slightly higher inboard than outboard and normal suspension travel takes place in the sweet spot either side of horizontal. Without detailed calculations that’s generally your best shot. Lowering the outer point of the upper arm would therefore be similar, but of course only for the upper arm while the lower remains unchanged. There are many suspension geometry programs that can calculate what impact that will have, I’m sure I’ve still got an ancient Excel based one on a floppy disk somewhere. BTW I raised this same issue when talking about the proposals for front camber options because an eccentric bushing can be used to raise the inboard end if you are already getting camber by other means no longer checked (hint hint). Logically, such changes are of more value on the front end where all the work is done to turn the car, and it can impact bump steer if your changes also level the tie rods. But moving the outer point on only the rear upper by a small amount seems likely to yield very little benefit. I suppose more likely good than bad and I certainly would not look the other way if someone is doing it, but if rule changes were made it could be dealt with.

So please explain again what you think an angled slot provides other than what I described above, perhaps I am still oblivious to your point.
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#106
infamousjim

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From a total Noob outsider point of view I'll also chime in with an uninvited opinion... My car is right about "normal SM height" and gets 2.6 max on one side and 2.5 on the other side... The car's first logbook is 11 year old, some stuff is certainly worn/bent/wasted. Maybe with my budget I "can't afford to race", and I don't expect to be upfront with truly well prepped cars (driving is another, bigger hurtle, but i'm working on it) but I'm all for cheap, simple ways to fix issues, keep racing, and stay a bit closer to the frontrunners.

 

Right or wrong, I can't shake my perception that some of the big shops don't want to give up their hard earned knowledge/stockpile of gray market parts (purposely bent subframes and spindles), and giant part bins of "this will work better than your current crap" stock parts.


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#107
Steve Scheifler

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I’m confident that in this one case I speak for the owner of this site when I say all opinions are invited!

And despite my history of trying to uncover and expose not-so-grey exploits and outright cheats over the years, I am also comfortable in saying that while most of the current big shops/teams are always looking for a little edge over the guys close to them they are not conspiring against those trying to work their way forward. They may not give up their last secret, but they will gladly help you get to the point where that matters. A good basic setup that everyone already knows and many use as a baseline at new tracks is good enough to get close almost anywhere, then you can start tweaking it to find those last tenths.

As for the rest and whether you technically “can afford to race”, the SCCA would collapse without guys just like you so do not let anyone make you feel extraneous or second class when it comes to the rules. If anything just the opposite is true.

For the record, we have never met or communicated in any way directly or indirectly, and I did not ask or pay you to post here. :)
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#108
Tom Hampton

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People may be ducking your question for various reasons including that it wasn’t very clear, leading to my doubts about your understanding. Why not simply spit out your exact concern or theory?

But since you persist, my thoughts. Obviously, getting more camber via the arm allows you to get more cam without going as low as you would otherwise need to. Running lower is better in some ways and wirse in others, so the slotted arm allows more flexibility to find a happy combination. That’s not news, it’s the whole point of this topic.

So please explain again what you think an angled slot provides other than what I described above, perhaps I am still oblivious to your point.

 

You have remarkable patience---in conjunction with your loquacious style.  If I used that many words it would just increase the odds of some of them being less "patient". 

 

I've only managed to show restraint.  My most polite responses are:

 

1.  Duh.

2.  To paraphrase the princess bride, "That adjustment doesn't do what you think it does..."

 


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#109
Tom Hampton

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Right or wrong, I can't shake my perception that some of the big shops don't want to give up their hard earned knowledge/stockpile of gray market parts (purposely bent subframes and spindles), and giant part bins of "this will work better than your current crap" stock parts.


I'm only a regional racer in Texas, so I can't comment outside of that.  I'm a budget guy just like you.  I can absolutely, unequivocally say that the race shops that I've worked with will bend over backwards to help folks like you and me.  From setups, to driving tips, to maybe the occasional ride along, or swapping cars, or sharing data, or even giving you a part (or an entire corner) and helping you get it on the car before the next session.  Maybe letting you work for race parts...etc. 

 

At the end of the day, I haven't seen a racer, shop owner, or crew member who would let another competitors weekend go to shit over a mechanical...or refuse to offer advice to a noob or intermediate driver.  if the competition is better, the racing is more fun...and safer.  Everyone wants more fun...safer(ish).  With rare exceptions of known rivalries, that also, really extends to competitors who race for position on-track.


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#110
infamousjim

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I'm only a regional racer in Texas, so I can't comment outside of that.  I'm a budget guy just like you.  I can absolutely, unequivocally say that the race shops that I've worked with will bend over backwards to help folks like you and me.  From setups, to driving tips, to maybe the occasional ride along, or swapping cars, or sharing data, or even giving you a part (or an entire corner) and helping you get it on the car before the next session.  Maybe letting you work for race parts...etc. 

 

At the end of the day, I haven't seen a racer, shop owner, or crew member who would let another competitors weekend go to shit over a mechanical...or refuse to offer advice to a noob or intermediate driver.  if the competition is better, the racing is more fun...and safer.  Everyone wants more fun...safer(ish).  With rare exceptions of known rivalries, that also, really extends to competitors who race for position on-track.

I realize my original post may have came off harsh or accusatory when I didn't really mean it to, I have seen much of the same that you have said. I understand that some have spent a lot of time and money developing "legal" parts or stockpiling spares, and because it directly affects their livelihood I understand why they may wish to protect certain advantages like saying no to simple, cheap, more attainable changes to get to a similar end-result.

 

That said, I haven't been around very long and it's quite possible that I'm totally wrong... and I wouldn't want to piss off the people who have invested and poured endless blood sweat and tears into SM.... I just like tweaks that allow cheap, easy mods to improve where things are time consuming or expensive. 


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#111
Ron Alan

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It is my position this is NOT the case and there is another reason why they were slotted that has not been identified.

If they were to be slotted towards the centerline of the vehicle at a downward angle, that would gain camber and enable a taller ride height, this removing the negatives of running lower (less suspension travel) while retaining the negative camber gained by running lower.

 

S

Ok...going to step way outside my limited knowledge and try to understand this. As I see it, we have 4 relatively fixed points(control arm bolts inner and outer) when the car is sitting static under load. Disregarding the rubber bushings for a minute...we then have an adjustable shock collar that we can move up and down which in turn lowers or raises the car. Since the upper control arm is the shortest in a horizontal plane, it truly has the most affect on camber as the car loads and unloads or is raised or lowered. And if that upper arm starts in a different location in reference to horizontal...in theory it will have a greater or lesser affect on camber under load conditions?  So by having a slotted outer bolt hole other than horizontal, the arm starts in a different location(up or down relative to horizontal)and thus changes its relative range of motion under load...which in turn affects camber under load?

 

Hmmm...I think I've completely confused myself! I'm not connecting something other than a horizontal slot affecting ride height. I think I do see something other than a horizontal slot changing camber through its range of motion( In theory)more.


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#112
BNaumann

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I can't take it anymore. You can slot the control arm in any direction you want. You can bend the control arm any shape you want. NOTHING MATTERS EXCEPT THE EFFECTIVE LENGTH. Draw a line from the inboard bolt to the outboard bolt. Measure that line. That is the only effect that the upper control arm has on the kinematics of the rear suspension.
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#113
Caveman-kwebb99

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The way I see it, we have a tire right now that IMO can take all the camber we can throw at it...  Supposedly Hoosier is gonna develop a new tire and we have no idea if that tire will like to be cambered more or less then the tire we have.

 

Powers has talked about actually testing this out and providing data, we actually talked a bit about this last week when we were drinking and watching Coyotes try to win a game lol...

 

I could personally care less if we approve a way to get more camber or not!  But I do personally believe it is an advantage!  


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#114
Steve Scheifler

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Let’s solve it by asking for a bias ply tire. :)
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#115
Caveman-kwebb99

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Let’s solve it by asking for a bias ply tire. :)

 

 

No If elected to office I would sign an executive order to allow a bigger RP to anyone that is camber challenged... A turbo Charger to anyone with a 1.6 that complains about being competitive...   Making Spec Miata Great Again!!!!!!!


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#116
steveracer

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^You forgot to undercut and ridicule anyone better/faster/smarter than you, otherwise you have my vote.


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#117
Caveman-kwebb99

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^You forgot to undercut and ridicule anyone better/faster/smarter than you, otherwise you have my vote.

 

 

It would take me to long to make that list lol :)


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#118
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infamousjim from Central Jersey, your connected, you only just don't know how.

Two time Drago (site owner) has roots in NJ. :bigsquaregrin:


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#119
BNaumann

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So regarding the original point (I think) of this thread, I was having a private conversation but decided to cut and paste here:

My only contribution to the poll is I simply want the ability to try more left side camber than I can currently get. I don't want to argue on the internet. What really bugs me is people getting hung up on the numbers. I can measure the car at least three different commonly used rollout and slip conditions and get very different numbers before we even start changing ride height. You can't simply say 4 is enough and 3 is not enough.

#120
EMatoy

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A 0.5 degree increase in camber only requires a change in length of 0.0769 inches of a suspension component that holds the wheel at a desired angle.

There are many ways to change the length. It could be an obvious slot as reported to have been done by Danny. You could also adjust many different parts of the sub frame, the knuckle or lower control arm.

Currently there are not any dimensions on these parts in the rules so you have to compare the part in question to a new one. Sure a slot is obvious- but will you visually see 0.0769 inches on a sub frame when compared to a new one? Would you see a 0.5 degree bend in a knuckle? Who actually has a new subframe (with a part number and in a factory bag) at a race to compare it to? How do you prove it was not tweaked due to contact? If the cam adjustment slots are worn and the upper control arm mounting bolt hole are worn how do you prove it was modified not wear from someone driving with the bolts lose when it was a street car for 200,000 miles? So now you might say publish dimensions and measure. What are the tolerances on each part? How precise can you measure a sub frame? Is the gain some want smaller than the tolerance stack up and measurement error?

Point is if you are cleaver and want to cheat on camber you can- this is not new. There are many ways it can't be measured and proven Danny simply brought it to everyone's attention. Why not take the cheat away, level the playing field, reduce cost and time spent? A 0.100 inch slot is almost free takes just a few minutes and removed any advantage (real or perceived). This is what my letter will ask for.
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